The goals of this application are to better understand alterations in the neural circuitry underlying the reinforcing actions of ethanol (EtOH). The overall hypothesis is that self-administration of EtOH within the posterior ventral tegmental area (VTA) produces downstream alterations that enhance synaptic function and promote the reinforcing effects of EtOH. Previous studies from our laboratory indicated that Wistar and alcohol-preferring (P) rats will self-infuse EtOH directly into the posterior VTA, whereas the anterior VTA does not support this behavior. In addition, the reinforcing effects of EtOH within the posterior VTA requires activation of DA neurons, and presumably involves information processing in VTA target regions. In this proposal, the effects of EtOH self-infusion into the posterior VTA on changes in protein expression in targeted limbic brain regions will be examined. Preliminary data indicated that P rats self-infusing EtOH into the posterior VTA showed increases in the expression of genes for proteins involved in neurite and dendritic spine outgrowth, suggesting increased synaptic function has developed in the nucleus accumbens (Acb) as a result of EtOH activation of VTA DA neurons. The present proposal will continue the initial study by examining changes in expression of synaptic proteins following EtOH self-administration into the posterior VTA using state-of-the-art proteomics analysis coupled to subcellular fractionation techniques to obtain samples of the Acb enriched in synaptic components. [unreadable] [unreadable]